Remibrutinib in Real-world Clinical Practice - a Germany Sub-study (REASSERT)

Inclusion Criteria: 7.2.1 Inclusion criteria Patients must meet all the following criteria to be eligible for inclusion in this study. 1. Patients with a confirmed diagnosis of primary CSU by the treating physician. 2. Aged at least 18 years on the date of enrollment. 3. Written informed consent of the patient to participate in the study and willingness to complete full follow-up period of 24 months. 4. Cohort-specific observational inclusion criteria: 1. Cohort 2: Inadequate control of CSU despite licensed dose or escalated sgH1-AH(s) (no other pre-treatment with exception of first generation H1-AH permitted) with decision (independent of study enrollment) to switch to remibrutinib treatment as per local label. 2. Cohort3: Any other treatment received in addition to H1-AH, any time during patients' CSU treatment history, with decision (independent of study enrollment) to switch to remibrutinib treatment as per local label. Note, occasional steroid rescue medication is out of scope for cohort definition. If a patient had been on continuous steroids for at least 3 weeks during treatment history, they will be included in cohort 3. Exclusion Criteria: Patients are excluded if they meet any of the following criteria: 1. Simultaneous participation in any investigational trial or simultaneous participation in another Novartis-sponsored non-interventional study with remibrutinib. 2. Patients within the safety follow-up phase of a previous interventional or non-interventional study. 3. Patients who received remibrutinib at any time in the past. 4. Patients not capable or willing to continuously provide ePRO/eDiary data via electronic means throughout the duration of the study. 5. Patients who are treated with remibrutinib outside of the local label.